1,1,2,3-tetrachloropropene (HCC-1230xa) represented by the formula CCl2═CClCH2Cl is a compound that is useful as a material for producing various fluorocarbons, and is also useful as a monomer component for producing various polymers.
As a method for producing HCC-1230xa, for example, Patent Literature 1 listed below discloses a method comprising removing HCl from 1,1,1,2,3-pentachloropropane (HCC-240db, CCl3CHClCH2Cl) in a liquid phase by using a FeCl3 (ferric chloride) catalyst. Patent Literature 2 listed below also discloses a method comprising removing HCl from HCC-240db in a liquid phase at a temperature of 103° C. or more by using a FeCl3 (ferric chloride) catalyst to directly produce HCC-1230xa from HCC-240db. However, these methods require a long reaction time due to the reaction in a liquid phase; and also have other problems such as high cost due to the use of a catalyst, and waste disposal. Therefore, these methods are not suitable for economical mass production.
Patent Literatures 3 and 4 listed below disclose a method for producing HCC-1230xa comprising subjecting 1,2,3-trichloropropane as a starting compound to a dehydrochlorination reaction with an alkali (NaOH) and a chlorination reaction with chlorine (Cl2), repeating these reactions to form 1,1,2,2,3-pentachloropropane (HCC-240aa), and then removing HCl from 1,1,2,2,3-pentachloropropane. However, this method requires improvement in many respects. For example, the yield is low; a multiple step reaction is required; a large amount of waste generated due to the use of an alkali must be disposed of; and continuous production is difficult because each reaction takes a long time.
Further, Patent Literature 5 listed below discloses that HCC-1230xa can be produced by reacting HCC-240db in a gas phase in the presence of a ZnCl2 catalyst supported on a porous carrier. However, this method requires further improvement in the suppression of side reactions; and also has problems such as high cost due to the use of a catalyst, and catalyst deactivation.
As described above, a process by which HCFC-1230xa can be easily and economically produced at a high yield has yet to be established.